COLL 41 |
| Derya Gulsen and Anuj Chauhan. Chemical Engineering Department, University of Florida, Room 237 CHE PO Box 116005, Gainesville, FL 32611 |
| The novel drug delivery systems seek to deliver drugs at a uniform rate for extended periods of time for more convenient, efficient drug delivery and reduced side effects. Our project aims to develop disposable soft contact lenses that can be used as vehicles for such a delivery system. The main idea is to encapsulate the ophthalmic drug formulations in nanoparticles and to disperse these drug-laden particles in the contact lens matrix. We focus on soft hydrogel lenses that are made of poly-2-hydroxyethyl methacrylate (HEMA) synthesized by bulk or solution free radical polymerization. Hydrophobic drugs are entrapped either inside microemulsion drops or liposomes. They are then incorporated into hydrogel matrix by subsequent polymerization from which they will diffuse into eye. We considered four kinds of O/W microemulsions: Tween 80 and Panadon SDK; Brij 97; Brij 97 and OTMS, and Tween 80, Panadon SDK and OTMS. The first two of these microemulsion systems become unstable on addition of HEMA monomers due to solubility of the surfactants in HEMA, leading to an opaque gel. The third and the fourth systems are stable due to a monolayer of silica around the oil drop that slows down the aggregation of microemulsion drops after HEMA addition. We characterize the particle-laden hydrogel by swelling, light-transmission and electron microscopy studies. The trapped particles in the hydrogel matrix are about 200 nm in size, which is smaller than the wavelength of the visible light rendering the gel transparent. After synthesizing the gel, we measured the drug release rates of a model hydrophobic drug, Lidocaine, and show that our proposed system can deliver therapeutic levels of drug for about 5 days. The drug delivery rates can be controlled by tailoring the microstructure of the hydrogel and manipulating the size, concentration and structure of the nanoparticles. Keywords: Microemulsions, ophthalmic drug-delivery, contact lenses, hydrogel, HEMA
|
|
ACS Award in Colloid and Surface Chemistry Symposium Honoring Clay Radke
Division of Colloid and Surface Chemistry |